Fuel The fuel pump doesn't stop priming and I can hear a hissing noise on the lower intake area (passenger side).

Trilldev123

Member
Dec 25, 2021
36
6
18
It's not an easy question to answer because you are using an aftermarket harness. Typically you can use an AOD ecu only with AOD specific wiring. Is there a wiring diagram provided for the harness? part number?

CHeck for voltage on pin 46 with the ecu pulled during key on and cranking. Ensure that you have zero voltage on this pin coming from the harness. (unsure if you tested this). However the aftermarket harness may not even be wired like this so it may not be a concern at all and a lot of these suggestions don't apply.
Also, I don't mind going ahead and doing ECU swaps. If it makes things easier. I'll eventually change a bunch of internal engine stuff after I get the car driving with the new wiring and if the original DA1 computer that I have won't work with this wiring then oh-well
 
  • Sponsors (?)


Trilldev123

Member
Dec 25, 2021
36
6
18
On page 8&9 in the booklet it calls out A9L and A9P you would wire the clutch switch as shown for the A9P with a manual trans. I'm running an 8LD ECU.
How did you run your red/blue NSS wire? I am having trouble with where I should put this single NSS wire. I'm not sure which color wire Is the ground within the clutch safety switch. I have 3 red and blue wires on the black plug (2 grouped together). 2 blue and yellow, and 2 black and white on the clear plug included picture shows exactly how mine is. I keep reading that the NSS wire from pin 30 wire should go to ground just to tell the computer if the car is in neutral or not, but is this NSS wire needing to be connected within the switch or a random ground spot on the chassis (My choice) ?
 

Attachments

  • D5A4C914-DD24-4055-8D57-5DEE40E83844.jpeg
    D5A4C914-DD24-4055-8D57-5DEE40E83844.jpeg
    82.1 KB · Views: 23
  • painless A9P computer instructions.PNG
    painless A9P computer instructions.PNG
    63 KB · Views: 23

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
39,490
15,333
224
I don't have my NSS hooked up and it works fine. It will start in any gear however.


It's not a neutral safety switch. It has nothing to do with the starter circuit. It's a Neutral Gear Switch. The NSS is jumpered out on a 5-spd car in the reverse light harness and not used at all on manual transmission cars. The 5-spd uses a clutch safety switch (brown plug in above photo).

The NGS is used to tell the ECU that the trans is in gear, and is wired in parallel with the clutch switch (white plug above). These two switches tell the ECU that the car is in nuetral, which affects idle quality slightly.
 

Trilldev123

Member
Dec 25, 2021
36
6
18

Mustang5L5

Mr.Kelley

General karthief

vristang

7991LXnSHO

Okay, so after spending some time learning about relays and going back over the instructions, I have finally figured it out. This is a lot to explain but I'll try my best. Basically in shorter terms, the factory EEC power relay is non-existant and the painless harness EEC power relay wasn't getting the constant power that the computer and relays need allowing the trigger wire to turn the relays on and off like normal. For the Hissing noise from the fuel pressure regulator, I removed the vacuum line off the tip and the adjustment screw came off with it. I think the adjustment was at the least amount of pressure possible allowing the fuel to just go back into the return easily. I threaded the screw in a decent amount and now the hissing is gone.

Being that both the factory fuel pump relay and painless harness fuel pump relay were hooked up at the same time. Both had Constant and key-on switch wires attached like normal with power going to them but, my factory EEC power relay was removed when I eliminated the old engine harness. But the new painless harness has an EEC power relay and I know both the fuel pump and EEC power relay connect. Since finding out relays have a constant 12v and a key on switched wire going to them I checked for constant 12v power on the painless harness with a voltmeter at the fuel pump relay and had nothing. I then traced down and figured out that I mistook the wire labeled "starter relay" for the ignition trigger wire and placed it wrong. This yellow wire is labeled  STARTER RELAY: This is a yellow, open ended wire. Connect this wire the the B+ side of the starter relay or to the positive side of the battery. This wire provides constant Battery 12v power to your computer and relays. I attached this wire to the middle threaded part of the starter relay, which wasn't providing the constant power to the fuse box, computer, relays, and wasn't providing the signal to the trigger wire to turn the relay off. After placing the starter relay wire in the correct spot I checked the painless harness for constant power and key on power at the relays and fuses and everything checked out. I then checked my green/ yellow trigger wire when I switched the key on with a volt meter and the numbers blipped and went down as a trigger wire should. I then disconnected the factory pink and black fuel pump wires from the factory fuel pump relay and hard wired the trigger wire to it and my pump primed for 3 seconds and shut off like normal and I even had the car running and idling.

Thank you everyone for the help. This was just me kinda-sorta rushing through the installation and not reading the fine print in the instructions given and just going off of the labels taped on the wires that painless has.
 
  • Like
Reactions: 1 users

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,388
3,091
194

@Mustang5L5

@Mr.Kelley

@General karthief

@vristang

@7991LXnSHO

Okay so now the car sounds like its cammed but theres no cam. I thought it was because the egr wasn’t plugged in but it doesn’t change. I set the timing to 12 degrees.
So is this a bad thing? :scratch: Voodoo cams cost a lot to get that sound.:jester:

Seriously, does your painless harness have the port to read codes? I suspect the surging idle checklist will cover this and you can have it idle smoothly.
 

Trilldev123

Member
Dec 25, 2021
36
6
18
So is this a bad thing? :scratch: Voodoo cams cost a lot to get that sound.:jester:

Seriously, does your painless harness have the port to read codes? I suspect the surging idle checklist will cover this and you can have it idle smoothly.
Lmao in my case yes it's bad. I wish it was supposed to sound like that cause it sounds bada**. I'll find the surging idle checklists later on and read through it.
 

Trilldev123

Member
Dec 25, 2021
36
6
18

7991LXnSHO

So since I have a 200amp alternator installed would that cause issues? referring to the surge list when it talked about grounds. The alternator comes with a 4 gauge power wire. Right now I just have the factory black wire from the starter relay to the engine block being the ground plus 2 other ground straps. The painless harness wires labeled "EEC ground" says to install to a clean ground source so I put a ring terminal on it and bolted it behind the passenger kick panel area with a bare surface.
 

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,388
3,091
194

7991LXnSHO

So since I have a 200amp alternator installed would that cause issues? referring to the surge list when it talked about grounds. The alternator comes with a 4 gauge power wire. Right now I just have the factory black wire from the starter relay to the engine block being the ground plus 2 other ground straps. The painless harness wires labeled "EEC ground" says to install to a clean ground source so I put a ring terminal on it and bolted it behind the passenger kick panel area with a bare surface.
The stock gauge wires will not handle 200 amps. Here is one alternator conversion thread. Melting wires are not likely to cause a bad idle. https://www.stangnet.com/mustang-forums/resources/3g-alternator-fox-upgrade.18/

Here is the surging idle checklist.
A vac leak or a loose PCV grommet can do bad things to your idle, but that’s only one possible issue.
 
  • Useful
Reactions: 1 user

Trilldev123

Member
Dec 25, 2021
36
6
18
The stock gauge wires will not handle 200 amps. Here is one alternator conversion thread. Melting wires are not likely to cause a bad idle. https://www.stangnet.com/mustang-forums/resources/3g-alternator-fox-upgrade.18/

Here is the surging idle checklist.
A vac leak or a loose PCV grommet can do bad things to your idle, but that’s only one possible issue.
the vaccum hose that wentto the PCV Valve was able to be slipped off easily. I tightened the hose clamp at the PCV and will try later
 

Trilldev123

Member
Dec 25, 2021
36
6
18
The stock gauge wires will not handle 200 amps. Here is one alternator conversion thread. Melting wires are not likely to cause a bad idle. https://www.stangnet.com/mustang-forums/resources/3g-alternator-fox-upgrade.18/

Here is the surging idle checklist.
A vac leak or a loose PCV grommet can do bad things to your idle, but that’s only one possible issue.
I figured out my issue. I didn't have a vacuum line going from the map sensor to the back of the intake. Idles are perfect now.
 
  • Like
Reactions: 1 user